During the next three years, some 2,000 older women throughout King, Pierce and Snohomish counties will get a special invitation in the mail from the Fred Hutchinson Cancer Research Center. This invitation is an opportunity to participate in a study that will help researchers understand the causes of breast cancer among women ages 65 to 79 -- a group that accounts for more than a third of newly diagnosed breast malignancies in the United States.

"The highest incidence of breast cancer is in this age group, and yet nearly all studies to date have excluded this population," says Janet Daling, Ph.D., who along with Kathleen Malone, Ph.D., is a lead investigator of this National Cancer Institute-funded study, called the Puget Sound Area Breast Cancer Evaluation, or PACE..

Women with and without a history of breast cancer will be targeted for this population-based study, which will allow for a greater understanding of the many components that affect an older woman's risk of developing breast cancer.

"Regardless of whether a woman has had breast cancer, she can help improve the understanding of the disease, and possibly how to prevent it, by taking part in the study," Daling says. "This type of research is only successful if both women with and without breast cancer agree to be interviewed."

By looking at factors such as lifestyle, genetics, medical and reproductive history, and use of hormones and other medications, researchers will try to determine why some older women get breast cancer and others don't.

All women invited to participate will be rigorously selected according to age and geographic region to ensure that the study accurately reflects the community as a whole. Those who've had breast cancer will be identified through a special database located at the Hutchinson Center called the Cancer Surveillance System. Those without a history of the disease will be selected, through a scientifically random process, from a list of all Medicare beneficiaries in the three-county region.

For the results to be scientifically meaningful, everyone selected for evaluation must take part.

"A very high percentage of those selected must agree to participate," says Daling, an investigator in the Public Health Sciences Division. "When a woman refuses to participate when called upon, she cannot be replaced, and an important piece of information is lost."

Those who accept the invitation will be interviewed about their health and lifestyle, and be asked to provide a small blood sample. The blood sample, however, is not a requirement for participation. Certified interviewers from the Hutchinson Center will come to the participant's home, office or wherever is most convenient to conduct the interview. While those studied will receive $10 for their time, the true value of their contribution is priceless.

"In one way or another, every woman is affected by breast cancer. We all know friends, co-workers, neighbors and family members who have had the disease," Daling says. "Each woman who agrees to be interviewed for PACE is directly contributing to a better understanding of breast cancer, regardless of whether she has had breast cancer herself."